@LeavesCat Well, i won't say much as it now relates to Series continuation from upcoming Light Novel Vol.14 onward (aka., spoiler for LN only readers).
But i would say that majority of political power of the Kingdom (aka., Nobility's & other higher ups) was destroyed during the Demon Invasion covered in LN Vol.6, because they had been mind-controlled by Apostle during that time and later on died during invasion.
So, basically there is no Political power aspect to look into, aka., everything is decided by the surviving royalty's, those being Liliana, her Mother and her younger Brother.
And like i said, Liliana had already given up her right to the throne when she went to make a deal (which was basically her getting married to the Prince in exchange for support) with the Empire in LN Vol.7.
Plus, Liliana doesn't really have much interest in ruling a nation, she is just doing her work as there is no one else currently to hand over the work to.